(1) Field of the Invention
The present invention relates to an electrodeposition coating composition, more particularly to a cationic electrodeposition coating composition which is free of lead and capable of forming a coating film showing good properties in both corrosion resistance and weather resistance.
(2) Description of Background Art
The electrodeposition coating method makes it possible to form a coating film showing good properties in durability, corrosion resistance, and the like, and has widely been used in an automobile, domestic article, other apparatus, etc. Taking the above advantages of the electrodeposition coating method, demand on an electrodeposition coating composition for use in one coating finish has recently been increased.
As the electrodeposition coating composition for use in one coating finish, an electrodeposition coating composition prepared by adding an acrylic resin to an epoxy resin, particularly a bisphenol type epoxy resin, is known in the art. However, the above electrodeposition coating composition has such drawbacks that a decreased epoxy resin content makes it impossible to obtain a satisfactory corrosion resistance, and an increased epoxy resin content so as to increase corrosion resistance makes it impossible to obtain a satisfactory weather resistance, resulting in making it impossible to obtain a satisfactory properties in both corrosion resistance and weather resistance.